Problem: CursorLineFold and CursorLineSign are only applied when
'cursorlineopt' contains "number" or is "both"
(Evgeni Chasnovski).
Solution: Apply those groups whenever 'cursorline' is set, independent
of 'cursorlineopt' (Vrushali Zampalkar).
fixes: vim/vim#20480closes: vim/vim#211121f8d3c44c5
Co-authored-by: Vrushali-Z <zampalkarvasu@gmail.com>